Natural polymers are very widespread in the world, which is why it is so important to know about the possibilities of their use. Chitin is the second most abundant reproducible natural polymer in nature; however, it is insoluble in water and basic solvents. Chitin is an unused waste of the food industry, for which there are possibilities of secondary management. The research led to obtaining a soluble, environmentally friendly form of chitin, which has found potential applications in the many fields, e.g., medicine, cosmetics, food and textile industries, agriculture, etc. The deacetylated form of chitin, which is chitosan, has a number of beneficial properties and wide possibilities of modification. Modification possibilities mean that we can obtain chitosan with the desired functional properties, facilitating, for example, the processing of this polymer and expanding the possibilities of its application, also as biomimetic materials. The review contains a rich description of the possibilities of modifying chitin and chitosan and the main directions of their application, and life cycle assessment (LCA)—from the source of the polymer through production materials to various applications with the reduction of waste.

Fungal pathogens cause significant yield losses of many important crops worldwide. They are commonly controlled with fungicides which may have negative impact on human health and the environment. A more sustainable plant protection can be based on carbohydrate biopolymers because they are biodegradable and may act as antifungal compounds, effective elicitors or carriers of active ingredients. We reviewed recent applications of three common polysaccharides (chitosan, alginate and cellulose) to crop protection against pathogenic fungi. We distinguished treatments dedicated for seed sowing material, field applications and coating of harvested fruits and vegetables. All reviewed biopolymers were used in the three types of treatments, therefore they proved to be versatile resources for development of plant protection products. Antifungal activity of the obtained polymer formulations and coatings is often enhanced by addition of biocontrol microorganisms, preservatives, plant extracts and essential oils. Carbohydrate polymers can also be used for controlled-release of pesticides. Rapid development of nanotechnology resulted in creating new promising methods of crop protection using nanoparticles, nano-/micro-carriers and electrospun nanofibers. To summarize this review we outline advantages and disadvantages of using carbohydrate biopolymers in plant protection.

Alginate-based materials are widely studied for biomedical use, but their limited mechanical properties and variable biocompatibility pose challenges. In this work, hybrid composites composed of alginate, calcium, and graphene oxide were fabricated using a freeze-drying method and cross-linked with calcium ions via calcium chloride at different concentrations. Structural and morphological features were assessed using SEM, EDS, ICP-MS, and BET analysis. The resulting composites exhibited a porous architecture, with calcium incorporation confirmed by elemental analysis. Surface characteristics and pore parameters were influenced by the presence of graphene oxide and the cross-linking process. The effects of the materials on haemostasis were evaluated through activated partial thromboplastin time (aPTT) and prothrombin time (PT) assays, revealing modulation of the intrinsic coagulation pathway without significant changes in the extrinsic pathway. In this study, we analysed the effect of alginate–graphene oxide composites on the viability of peripheral blood mononuclear (PBM) cells and human foreskin fibroblasts from the Hs68 cell line. We also assessed the genotoxic potential of alginate–graphene oxide composites on these cells. Our results showed no cyto- or genotoxic effects of the material on either cell type. These findings suggest the biocompatibility and safe character of alginate–graphene oxide composites for use with blood and skin cells.